Exchange-Correlation Effects in a Finite-Temperature Quasi-One-Dimensional Electron Gas

Abstract

The exchange-correlation effects in a finite-temperature quasi-one-dimensional electron gas, using the self-consistent mean-field theory of Singwi, Tosi, Land, and Sjölander have been theoretically investigated. The influence of temperature T is elucidated by calculating different static properties (viz. static structure factor, pair-correlation function, static density susceptibility, and free exchange-correlation energy) and the plasmon excitation spectra over a wide range of T and electron number density. Noticeable dependence on T is found, with an interesting interplay between short-range electron correlations and T. More precisely, the pair-correlation function at small separation and for a given density first becomes stronger (i.e., its value decreases) with increasing T and then weakens monotonically above a critical T, whose value increases with reduction in density. On the other hand, the plasmon energy shows a consistent blue shift with rising T. However, the critical wave vector at which plasmons enter the single electron–hole pair continuum, decreases with T. For highlighting the correction due to short-range correlations, the results have been compared with the predictions of random-phase approximation (RPA). As for the zero-T case, the RPA is found to be reliable only in the high density domain.